Signal distributor



@4M l l5 S. Jv. ELLIOTT EIAL4 SIGNAL DISTRIBUTOR Filed July 18, `1942 2 Sheets-Sheet l nu@v ATTORNEY 0f 22 1946 s. J. ELLIQTT Erm. 2,409,617

S IGNAL DISTRIBUTOR Filed July 18, 1942 2 Sheets-Sheet 2.

GAA/ao ByC/0 SM. T/-lo/gmsl TIME Q Q M0( n l Arma/yp Patented Oct. 22, 1946' SIGNAL DISTRIBUTOR Stanley J. Elliott, Forest Hills, N. Y., Ole M. Hovgaard, Murray Hill, N. J., and Rudolph F. Mallna, Hastings-on-Hudson,

and Frank M.

Thomas, Jackson Heights, N. Y., assignors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application July 18, 1942, Serial No. 451,506

6 Claims.

This invention relates to signal distributors, and particularly to devices of that character which are associated with radio receiving equipment.

The object of the invention is to provide an efficient low capacity signal distributor particularly adapted for use in association with the receiving circuits on intercepter airplanes provided with equipment to transmit radio signals which are reflected back from other airplanes to the intercepter planes and thus furnish information as to the location of such airplanes. The device, however, is of general application.

A feature of the invention is the provision of means for preventing chatter of the contact springs of the signal distributor, which springs are rapidly actuated to make and break the radio signal receiving circuit.

Another feature is the provision of means for permitting adjustment of the contacts Without the necessity of dismantling the device.

Other features will appear from the detailed description and the appended claims.

In the drawings:

Fig. 1 is a plan view of the device;

Fig. 2 is a side View partially in section;

Fig. 3 is a sectional View on line 3-3 of Fig. 2;

Fig. 4 illustrates a circuit arrangement with which the switch may be used; and

Fig. '5 is a view to show the relative closures and openings of two sets of contacts in the circuit arrangement.

Referring now to the drawings, Fig. 2, l and ll indicate a pairof housings, I0 indicating the upper housing and II indicating the lower housing. This pair of housings or casings is secured together by clamps I2. These casings house two sets of similar equipment; that is, each housing contains four pairs of contacts, the four pairs in the upper housing I0 being indicated by the numerals I, 2, 3 and 4, Figs. 1 and 3. The housings also contain other equipment for performing the necessary operations to open and close these contacts as required to receive the radio impulses. Of the four pairs of similar contacts I, 2, 3, and 4 in the lower housing II, only two can be seen in the figures, Fig. 2. These two are indicated by the numbers I and 2. These two sets or decks of four pairs of contacts as they will hereinafter be called, are rapidly actuated by a sleeve member I3, Fig. 2, preferably of hard rubber, which is eccentrically mounted with respect to the shaft assembly 28, 31. This sleeve is driven by an electric motor mounted in casing I4, as will be later described in detail. The leads to the motor are indicated at M. The lower four contact pairs I, 2, 3, 4, which for convenience will hereinafter be called the lower deck contacts, Fig. 5, serve to selectively connect the four receiving antenna circuits on the airplane to an amplifier, Fig. 4. The upper four contact pairs I, 2, 3, and 4, which for convenience will hereinafter be called the upper deck contacts, serve to connect the output of the amplifier to a suitable indicating device, this connection being made selectively and synchronously with the lower deck contacts. The lower deck contacts are closed shortly before the upper deck contacts, Fig. 5, and the lower deck contacts are opened shortly after the upper deck contacts have opened. When so operated, noise in the output circuit, which otherwise would be caused by switching the antenna circuits in and out, is prevented from reaching the indicating equipment, since due to this arrangement the indicating circuits are not connected to the amplifier when the antenna circuits are being connected and disconnected.

The specific construction and arrangement of the two decks of contacts I, 2, 3, 4 by means of which we have succeeded in eliminating contact chatter will now be described.

The four socket assemblies I5, I6, I1, and I8, Fig. 1 on the upper housing which support the Contact springs I9, 20, 2I, and 22 are similar coaxial conductor sockets. The four socket assemblies on the lower housing are similar. Referring, for example, to'socket I8 of the upper housing shown in detail in Fig. 3, this socket comprises a metal sleeve member 23 containing two insulating washers 24, 25, which support a stud 26 having a slot into which the contact spring 22 of contact 4 which may be of Phosphor bronze, is forced and anchored by rivets. Each spring has its free end looped back on itself and riveted to the body portion of the spring as shown. It is essential that these loops be formed substantially as shown, that is, that the side s be straight in order to give maximum stiffness to the structure. We discovered that this is the construction which eliminates chatter. If the side s is not straight the spring chatters when rapidly actuated by the sleeve I3. By having the side s straight, a condition is approached, due to not working the member in bending but in compression, that maximum stiffness or rigidity is attained. We prefer to so shape the spring as to have as nearly as possible three straight sides with sharp radii, that is, to approach a rectangular form. We discovered that no chatter occurs on the make or break of springs constructed and mounted in this manner even at high speeds oi rotation of the sleeve I3 which actuates the four sets oi contacts of each deck. Although the shaft of motor I4, through the coupling 21, drives the shaft 28 at a high rate of speed, for example 1,800 revolutions per minute, the sleeve I3 itself which actually engages the looped portions of the springs of the upper and lower contact sets actually rotates very slowly in the opposite direction on its ball bearing mounting, and effects the make and break of the contacts I, 2, 3, 4 by a reciprocating motion due to the following construction: A shaft i of hard rubber carries the sleeve i3 also of hard rubber. Ball bearings 3l, 32 are provided, their outer races secured to the sleeve I3 and their inner races to the shaft 38. The ends of shaft 3i) fit into eccentrically located apertures in members 33, 34. The lower member 33 is integral with shaft 28. Intermediate shaft 28 and member 33 is a ball bearing 35 mounted in a bearing plate 36. The upper member 34 is integral with a member 31 which has a ball bearing 33 in bearing plate 39. Since the shait 2B and upper bearing shaft 3'! are central and the apertures for shaft 3B are eccentric, it will be evident that the sleeve or cam i3 has a reciprocating motion, as pointed out above, which results in four makes and breaks oi the upper and lower deck contacts for each revolution of the shaft 23 which is driven by the motor.

We also provide an arrangement whereby the closed period of each contact can be adjusted independently from outside the casing even when the signal distributor is running, which facilitates adjustment operations. In the signal distributor the contacts are all normally closed. The contact force may be dened as the minimum force required to open the closed contacts when there is clearance between the contact springs and the sleeve or cam i3. The arrangement for adjusting the upper deck contacts can be best seen in Fig. 2. A similar arrangement is provided ior the lower set. Each housing ID and I I contains a phenol `libre insulating disc 56, Fig. 2, and each disc is secured a plate 44 of Phosphor bronce secured to said disc by screws. The screws 51 for the upper plate 44 may be seen in Fig. 3. The plate 44 carries the upper four contact studs, which may be of brass, with which the loops of contact springs I9, 2D, 2|, 22, Fig. 3, respectively, normally engage. Four hexagonal socket set screws 40, 4I, 42, 43, Fig. 3, mounted in tapped holes in the ends of arms 45, 46, 41, and i8 are accessible through holes 50, Fig. 2, in the upper housing I0. These screws bear against the body of plate 44. By turning them in and out by a suitable tool inserted in. the sockets through the openings in the housing Il! the radial positions of the stud contacts may be altered.

A precisely similar arrangement is provided for adjusting the contacts I, 2, 3, 4, in the lower housing II. The holes in the lower housing II are designated 50'.

As shown schematically in Fig. 4, the four antennas hereinbefore mentioned are connected to the central coaxial conductors associated with the lower deck contacts two of which conductors are shown structurally in Fig. 2 and designated C101 and C303. The other two diametrically opposite central coaxial conductors 02C2 and C401 assoelated with the lower deck contacts cannot be seen in Fig. 2. The four central coaxial conductors associated with the lower deck contacts are a part of the four input circuits from the :four antennas respectively.

As shown in Figs. l, 2 and 4, a similar arrangement is provided for the output circuits from the arnpliiier, the four central coaxial conductors C101, C202, C303, 04C4 shown structurally in Fig. l, being associated with the upper deck contacts.

As shown in Fig. 4, the four input central coaxial conductors C101, C202, C303 and 04C4 associated with the lower deck contacts I, 2, 3, 4 are successively connected by said contacts I, 2, 3, 4 to conductor Il and thence to the amplifier. The output circuit of the amplifier, connected to conductor 1I, is successively connected by contacts i, 2, 3, i of the upper deck to the four central coaxial conductors C101, C202, C303, 04C4 and thence to the indicating devices.

When it is desired to have access to the equipment in the upper housing Ill, it is merely necessary to remove the screws E!! which secure the cover 52 to the upper housing. When it is desired to have access to the equipment in the lower housing, it is merely necessary to remove screws such as 53, which secure the upper and lower housings to the mounting assembly plate 55 and elevate the entire unit, the shaft 28 being thus removed from the hose coupling 21,

As described. the shaft assembly which carries the eccentrically mounted contact actuator consists oi a shaft 30 0i hard rubber, the sleeve or contact actuator i3 of hard rubber, the ball bearings Ei, for the sleeve, and a pair of members S3, 34 which have the oi-center apertures for the shaft Sil. The members 32, 34 are provided with counterbalancing weights to prevent vibration; that is, to balance the rotating structure. This shaft assembly is cheap to manufacture and eilicient in operation.

The base coupling shown is of soft gum vulcanized rubber and eliminates critical adiustments and reduces vibration.

What is claimed is:

l. ln a signal distributor, a ser; of stationary; contacts, a series of movable contacts engaging raid stationary contacts, each of said movable contacts being in the vform of a resilient spring anchored at one end and havinr its [ree end looped back on itself and ancho-red to the body portion @i the spring and contact actuating member adapted to said loops in succession to force them out of Contact with the respective stationary contacts.

2. In a signal distributor, a series of Contact studs arranger'. in a circle, a series of movable contact members in the form of resilient springe, anchored at one end and having loops at the other end normally engaging said contact studs, and a member mounted eccentrically and adapted to open said contacts in succession by forcing said loops out of contact with said studs.

Tin a signal distributor, a series of contact a series of movable spring contact members normally engaging said studs, s id members being` anchored at and having loops at their other ends, each. loop having a number of substantiaily straight sides, and means for successively forcing said members out of contact with said studs.

4. In a signal distributor, a series ol contact studs, a serios of movable contact members in the i'orm of flat springs anchored at one end and having their free ends bent back ou themselves and secured to the body portion of the spring to form loops normally engaging said studs,` the porcontact members of resilient spring metal anchored at one end and at their other ends being formed in substantially rectangular loops which encircle and engage said studs, and an actuating member to successively force said loops out of contact with said studs.

STANLEY J. ELLIOTT. OLE M. HOVGAARD. RUDOLPH F. MALLINA. FRANK M. THOMAS. 

